Unless otherwise indicated herein, the materials described in this section are not prior art to the claims and are not admitted to be prior art by inclusion in this section.
A cellular wireless network may include a number of base stations that radiate to define wireless coverage areas, such as cells and cell sectors, in which user equipment devices (UEs) such as cell phones, tablet computers, tracking devices, embedded wireless modules, and other wirelessly equipped communication devices, can operate. In turn, each base station may be coupled with network infrastructure that provides connectivity with one or more transport networks, such as the public switched telephone network (PSTN) and/or a packet-switched network such as the Internet for instance. With this arrangement, a UE within coverage of the network may engage in air interface communication with a base station and may thereby communicate via the base station with various remote network entities or with other UEs.
In an example arrangement, the network infrastructure may include one or more gateways or similar components that provide connectivity with a packet-switched network so as to support various communication services. For instance, the infrastructure may include gateways that support general packet-data communications, such as general web browsing, file transfer, and the like, and/or real-time packet-based communications such as voice over Internet Protocol (VoIP) and streaming media for instance.
When a UE powers on or moves into the coverage of a base station, the UE engages in a process of registering or “attaching” with the network, which may trigger setup of various communication channels for the UE or reservation of various communication resources for the UE. For example, in a network operating according to the Long Term Evolution (LTE) protocol, a UE transmits an attach request message to the base station, which the base station forwards to a controller called a mobility management entity (MME). In response, the MME then invokes a process to authenticate and authorize the UE and retrieves a service profile of the UE from a subscription database and stores the profile for later reference during service invocation to determine one or more services that the UE is authorized to use. Further, the MME engages in signaling with the base station and with a serving gateway (SGW) to set up one or more bearer connections extending between the UE and a packet data network gateway (PGW), including for each bearer connection a radio bearer between the UE and the base station and an access bearer between the base station and the PGW. Further, the PGW may assign an Internet Protocol (IP) address for use by the UE, and to the extent the PGW supports communication with particular servers or systems, the PGW may register with those servers or systems on behalf of the UE.
Once these connections are established, the UE may then communicate bearer data (e.g., application layer communications such as web browsing and VoIP setup signaling) with various remote entities. In particular, as the base station serves the UE, bearer data may pass over a bearer connection from the UE to the base station to the PGW, and from the PGW over the packet-switched network to a remote entity. Likewise, communications destined to the UE from a remote entity may pass to the PGW serving the UE, then over a bearer connection from the PGW to the base station to the UE.
Furthermore, as the UE is served by the network, the UE may work with the network to establish additional bearers as needed. For example, if a UE subscribes to VoIP service, the UE may engage in VoIP call setup signaling over a VoIP signaling bearer that was established when the UE attached, and, responsive to signaling from the UE, the network may engage in a process similar to that discussed above, to establish a dedicated VoIP bearer for carrying VoIP bearer data (e.g., packetized voice) to and from the UE. Other examples are possible as well.